Confirm setbacks, lot coverage, and zoning for your lot

Start here

For a single-story addition, the binding zoning constraints aren't height or FAR — they're setbacks and lot coverage. Both are public, both are tied to your specific zone, and both are looked up in the same place.

How to do it

1. Open the Renton GIS Hub and search your address.
2. Note the zone designation — most single-family Renton neighborhoods are R-8, R-10, or R-14.
3. For R-8, look up the rules in RMC 4-2-110A. For R-10/R-14, the table is in RMC 4-2-110E. Both sections are also reachable through the Municode RMC Title 4 index.

What you're looking for

• Front setback. R-8 zones typically require a 20-ft front setback. A front addition is the most setback-sensitive geometry; check whether you're already close to the line.
• Side setbacks. R-8 typically requires 5 ft on each side. Many older Renton ramblers sit close to a side property line; check before assuming a side bump-out works.
• Rear setback. Generally 20–25 ft; rear is usually the most flexible direction.
• Lot coverage. The footprint of all structures as a percentage of the lot. Confirm the R-8 cap from the code table directly — R-8 is commonly cited at 35–45% coverage but verify the exact number from RMC 4-2-110A before relying on it.

What this tells you

• Room on all constraints? The addition is feasible from a zoning standpoint. Move on to the permit-history check.
• At lot-coverage cap already? A full addition isn't realistic without a variance. An interior-only remodel may be the right shape.
• Non-conforming side? Plan around it — push the addition in a different direction or talk to Renton CED about a variance or administrative adjustment.